Page 1 of 2 Next >>Having tasted competition success at the Pikes Peak Hill Climb in 1986 and 1987 with the Sport Quattro S1, Audi of America had even more ambitious plans for the 1988 season; the hugely competitive Trans-Am championship. This would provide the perfect setting to show the (performance) benefits of the 'quattro' all-wheel drive system were not limited to slippery rally but also meant Audi had to develop the company's first ever circuit racer.

Audi used the 200 Quattro as the basis for the new racer, which was known internally as the R4. Although the Trans-Am rules were very liberal, Audi retained the road car shell and suspension configuration. For safety reasons a steel tubular roll-cage was welded into the existing chassis, which also greatly improved the rigidity. Compared to the road car, the suspension geometry was also substantially altered to meet the demands of racing.

For homologation purposes, the new racer's engine also had to be based on a production unit. Audi opted for the turbocharged straight five engine with the single overhead camshaft head. Among the numerous modifications were a new aluminium crankcase, large valves and the addition of a second pump to ensure the fuel supply was sufficient. With the boost of the turbo set at around 3 bar, the 2.1 litre engine produced around 510 bhp at the start of the season.

The rest of the drivetrain was carried over from the earlier Quattro rally cars and included a six-speed gearbox. That was one more gear than the governing body SCCA allowed for, so the 200 Quattro was raced with one gear blanked off. An integral part of the sophisticated drivetrain was of course the quattro all-wheel drive system. This consisted of central Torsen differential and limited slip differential on both the front and rear axles.

Audi engineers fitted the production-derived chassis with a fibreglass reinforced plastic body, which loosely resembled the road going 200. Measuring close to five metres in length and over two metres in width, this was the largest racing car Audi had ever produced. To determine the exact design of the body and aerodynamic devices, the engineers spent a considerable amount of time in the wind-tunnel. To improve the weight balance, the driver's seat was moved back by 40 cm. Page 1 of 2 Next >>